Dissociation of electron-hole pairs interacting with triplet excitons in amorphous molecular semiconductors

Давиденко, Н. А.; Kuvshinsky, N. G.

doi:10.1002/(sici)1099-0712(199709)7:5<255::aid-amo316>3.0.co;2-w

Cited by 13 publications

(6 citation statements)

References 3 publications

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“…In earlier works [2,14,15], it was shown that the EHP lifetime in PEPK films with ICTC could be tens to hundreds of seconds at room temperature as a result of the existence of a positive potential barrier for hole transfer from the carbazole moiety of PEPK to an ICTC molecule upon EHP annihilation and preferably the triplet spin state of EHP. Furthermore, PEPK films contain hole traps in the vicinity of ICTC molecules [16,17], which also favor the formation of latent image by trapping photogenerated holes.…”

Section: Resultsmentioning

confidence: 99%

Holographic Recording Media Based on Systems with Intramolecular and Intermolecular Charge Transfer

et al. 2005

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Information characteristics of holographic recording media based on poly( N -epoxypropylcarbazole) films containing charge-transfer systems as photogeneration sites were studied, in which donor and acceptor molecules (or their fragments) either formed adducts between one another or were covalently bound by polymethylene spacer groups or by a system of conjugated π bonds. The recording media based on compounds with intramolecular charge transfer over a system of conjugated bonds for recording holograms using the photothermoplastic method exhibit an narrower intense spectral sensitivity band and a high holographic sensitivity. In these media, the effect of prolonged storage of latent image before the development of a hologram was revealed and explained.

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Section: Resultsmentioning

confidence: 99%

Holographic Recording Media Based on Systems with Intramolecular and Intermolecular Charge Transfer

et al. 2005

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“…The choice of MC, PC1, and PC2 for the studies was determined by the fact that the profiles of the spectra and the absorption maximums for these dyes in PS films are similar and result from only one electronic transition. But in AMS, the neutral dye MC, whose molecular structure is similar to that of molecules of the organic compounds with intramolecular charge transfer [10], may be considered as a site of photogeneration of both holes and electrons [11]. The dye PD1 plays a role of a photogeneration site for holes, whereas PD2 acts as a photogeneration site for electrons.…”

Section: Methodsmentioning

confidence: 99%

“…The dye PD1 plays a role of a photogeneration site for holes, whereas PD2 acts as a photogeneration site for electrons. This is determined by the situation that the colored ionic organic entities PC1 and PC2 have opposite electric charges and their HOMO and LUMO are substantially different [11]. Amorphous molecular semiconductors containing carbazole groups exhibit hole conductivity, and films based on the polymers poly( N -vinylcarbazole) (PVK) or poly( Nepoxypropylcarbazole) (PEPK) are widely used in holographic and electrographic recording media [4].…”

Section: Methodsmentioning

confidence: 99%

“…Hence polymer films doped with the monomer Nepoxypropylcarbazole (EPK) are convenient for studying intermolecular hole transport processes. Electron acceptors based on fluorenones are used in AMS for creating electronic conductivity, and hence polymer films doped with TNF are convenient for studies of intermolecular electron transport processes [11].…”

Section: Methodsmentioning

confidence: 99%

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Photogeneration of holes and electrons in amorphous molecular semiconductors with neutral and ionic organic dyes

et al. 2005

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Photoconducting properties of amorphous molecular semiconductors based on polystyrene films doped with tetranitrofluorenone and merocyanine or an anionic polymethine dye, or with epoxypropylcarbazole and merocyanine or a cationic polymethine dye were studied. The former type of the films is characterized by electron conductivity, whereas the latter type by hole conductivity. The activation energy for photogeneration of mobile charge carriers increases on passing from a merocyanine dye to ionic dyes and decreases with a growth in quantum energy of excitation light for the films of the former type, but does not depend on the light quantum energy for the films of the latter type. It was concluded that the activation energy of photogeneration is determined by electrostatic interaction of a photogenerated charge carrier with the ionized photogeneration site or a counterion for neutral and ionic dyes, respectively. At low dissipation rates of the excess thermal energy of excited dye molecules via electron-nucleus interaction, photogenerated electrons have a possibility to travel over a long distance from the photogeneration site as compared with holes.

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“…However, annihilation occurs in the case when the electron-hole pair is found in a singlet (S) spin state. If the electron-hole pair is found in one of the three possible triplet states (T 0 , T -, T + ), then the probability of dissociation increases [11][12][13][14][15][16]. The latter is connected with the fact that the lifetime of the triplet electron-hole pairs is longer than the singlet lifetime.…”

Section: Introductionmentioning

confidence: 99%

Sensitization of photoconductivity in ferrocene-containing oligomer by squarylium and merocyanine dyes

et al. 2011

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We have studied the photoconducting properties of films of ferrocene-containing oligomer with additives of squarylium and merocyanine dyes based on ferrocene and tetranitrofluorene in the dye absorption region. We have studied the characteristic features of the effect of an external magnetic field on the photocurrents. After the magnetic field is turned on, the photocurrent increases in the samples with squarylium dye and decreases in the samples with merocyanine dye. We discuss the hypothesis that in the first case, as a result of an internal photoelectric effect, predominantly triplet charge pairs are formed, while in the second case predominantly singlet charge pairs are formed. The latter may be one of the reasons for the higher photoconductivity of films with squarylium dye compared with merocyanine dye.Introduction. Films of polymer composites containing derivatives of ferrocene (Fe(C 5 H 5 ) 2 ) [1-3] may have photo-semiconductor properties [4,5]. This is attractive for application of ferrocene-containing polymer composite films in data media, for example for optical data recording and storage. Photoconductivity of polymer composite films in the visible region of the spectrum can be provided by organic dye additives, the molecules of which, after absorption of light energy, are capable of photogeneration of nonequilibrium charge carriers [6]. However, the possibility of sensitization of the photoconductivity of polymer composite films by organic dyes containing ferrocene substituents has not been studied. In this work, we have carried out a comparative study of the photoconductivity of polymer composite films based on a compound with ferrocene substituents, for which we used squaraine [7] and the intraionic dye merocyanine based on ferrocene and tetranitrofluorene as the centers for absorption of light and centers for photogeneration of charge carriers.Samples and Experimental Procedure. To prepare the polymer composite films, we used a ferrocene-containing oligomer (F1):

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Dissociation of electron-hole pairs interacting with triplet excitons in amorphous molecular semiconductors

Cited by 13 publications

References 3 publications

Holographic Recording Media Based on Systems with Intramolecular and Intermolecular Charge Transfer

Holographic Recording Media Based on Systems with Intramolecular and Intermolecular Charge Transfer

Photogeneration of holes and electrons in amorphous molecular semiconductors with neutral and ionic organic dyes

Sensitization of photoconductivity in ferrocene-containing oligomer by squarylium and merocyanine dyes

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